This invention relates generally to a method of contacting catalyst particles with a liquid and a gas and, more specifically, to a liquid phase reaction method using a particulate catalyst. The present invention is also directed to a device useful for carrying out the above method.
In order to uniformly mix catalyst particles with a gas and a liquid and to effectively carry out a catalytic reaction, it has been a general practice to use a stirrer. In this case, however, the catalyst particles are gradually physically pulverized as the reaction is continued for a long period of time, especially when the catalyst particles have low mechanical strengths and are fragile. The pulverized particles are entrained by the product stream discharged from the reactor to cause a change in the concentration of the catalyst in the reactor and to contaminate the product.
For example, U.S. Pat. No. 5,155,261 discloses a process for producing acetic acid by reacting methanol in a solvent with carbon monoxide in the presence of an alkyl iodide and a solid catalyst containing a rhodium complex supported on a porous, cross-linked vinyl pyridine resin carrier. Because the vinyl pyridine resin is gradually abraded or pulverized as the carbonylation is continued, the pulverization of the catalyst not only causes the reduction of the catalyst life but also requires the separation of the pulverized powder from the reaction product. Since the rhodium-supported catalyst is very expensive, the pulverization of the catalyst poses a serious problem.